Nutritional status and yield of sweet potato in response to nitrogen application management using chlorophyll meter

• Grant number: 21/05039-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2021
• End date: August 31, 2022
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Adalton Mazetti Fernandes
• Grantee: Arthur Victor de Oliveira
• Host Institution: Centro de Raízes e Amidos Tropicais (CERAT). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Nitrogen (N) is the second most taken-up nutrient by sweet potatoes (Ipomoea potatoes). Low N supply limits sweet potato yields, but oversupply increases vegetative growth and reduces storage root yield. Therefore, a balanced supply of N for sweet potatoes is essential to obtain high root yields. This work aims to evaluate the nutritional status and yield of sweet potatoes in response to N fertilization management using a chlorophyll meter. For this purpose, it is sought to establish the best N sufficiency index (NSI) to manage N fertilization in sweet potatoes. The experiment will be conducted in two locations, in a randomized block design, in a 2+6x2 factorial scheme, with four replications. The treatments will be composed of conventional N fertilization (50 kg ha-1 N), reference N fertilization (150 kg ha-1), and six NSI values (90%, 91%, 92%, 93%, 94%, and 95%) associated with two N application criteria (10 or 15 kg ha-1 N for each 1.0 percentage point below the treatment NSI value). The following will be evaluated: Relative chlorophyll index and N concentration in the leaves, nutrient concentration in the diagnostic leaves, number, mean weight, and yield of roots, NSI and N rate of maximum technical efficiency, and correlation analysis, and starch content in roots. The data obtained will be submitted to analysis of variance separately by the site. The means of factorial components referring to the N application criteria will be compared b.y the LSD test (pd0.05). The effects of NSI values will be evaluated by regression analysis (pd0.05). Orthogonal contrasts will be performed between the factorial treatments and the conventional and reference treatments. (AU)